Ed is right. Apple won't replace the sensor, only the phone. So if your sensor is truly defective and not something that they can get working for you and you also can't replace your phone, you're screwed. However, I don't really understand why you couldn't simply back the phone up into iTunes, wipe it before giving it to Apple, and then restore the new device as your old device in iTunes. Everything would be identical. That is, unless your work prohibits backing up of any kind, in which case, like I said, you'd be screwed.

And what about the home button flex it self...
Its not problem to replace it?
Its not soldered to the flex or something like that wright ?!

Tnx

I'm really not sure what to tell you other than it would be incredibly difficult to replace yourself, and that's if it's even possible because like you said, it could be soldered (I just don't know). I'd certainly advise against it, but hey, it's your phone.

The Touch ID sensor is tied to the CPU so if you replace the Touch ID sensor it won't work. This is suppose to be a security feature so if someone stole your phone and replaced the sensor your phone with a rigged one your phone will reject it.

This all sounds like a hypothetical situation.
If something goes wrong with your home button contact Apple. Check the warranty for your country I know warranties can differ from country to country it's all on Apples website.
If something goes wrong with the Touch ID hardware why concern yourself with replacing the home button when the phone won't work properly if it's done.

I would think that Touch ID effects batt life slightly. The ring around the home button acts as a capacitive touch switch that turns the sensor on and off when a finger is present. So the sensor isn't on all the time.